MRI is a diagnostic procedure that uses a combination of a large magnet, radio waves, and a computer to produce detailed images of organs and structures within the body. An MRI is often used:

• to examine the heart, brain, liver, pancreas, male and female reproductive organs, knees, shoulders, spine, and other body areas.

• to assess blood flow.

• to detect tumors and diagnose many forms of cancer.

• to evaluate infections.

• to assess injuries to bones and joints.

MRI can be performed on an outpatient basis, or as part of inpatient care. The MRI machine is a large, cylindrical (tube-shaped) machine that creates a strong magnetic field around the patient. This magnetic field, along with radio waves, alters the hydrogen atoms' natural alignment in the body. Computers are then used to form 2-dimensional and 3-dimensional images of a body based on the activity of the hydrogen atoms. Unlike CT, MRI does not use radiation.

The MRI process goes through the following steps:

1. A magnetic field is created and pulses of radio waves are sent from the scanner.
   
   
2. The radio waves tilt the nuclei of the atoms in your body out of their normal position.
   
   
3. As the nuclei realign back into their usual position, the nuclei send out radio signals.
   
   
4. These signals are received by a computer that analyzes and converts them into an image of the part of the body being examined.
   
   
5. This image appears on a viewing monitor.

Although each hospital may have specific protocols in place, generally, an MRI procedure follows this process:

1. Because of the strong magnetic field, the patient must remove all jewelry and metal objects such as hairpins or barrettes, hearing aids, eyeglasses, and dental pieces.
   
   
2. If a contrast medication and/or sedative is to be given by an intravenous line (IV), an IV line will be started in your hand or arm. If the contrast is to be taken by mouth, the patient will be given the contrast to swallow.
   
   
3. The patient lies on a table that slides into the scanner.
   
   
4. The MRI staff will be in another room where the scanner controls are located. However, the MRI staff will be in constant view of the patient through a window. Speakers inside the scanner will enable the staff to communicate with and hear the patient. The patient will have a call bell so that he/she can let the staff know if he/she has any problems during the procedure.
   
   
5. During the scanning process, a knocking noise occurs as the magnetic field is created and pulses of radio waves are sent from the scanner. The patient may be given headphones to wear to help block out the noises from the MRI scanner and hear any messages or instructions from the technologist.
   
   
6. It is important that the patient remain very still during the examination.
   
   
7. At intervals, the patient may be instructed to hold his/her breath, or to not breathe, for a few seconds, depending on the body part being examined. The patient will then be told when he/she can breathe.
   
   
8. The technologist will be watching the patient at all times and will be in constant communication.